1	package antlr.collections;
2	
3	import java.util.Enumeration;
4	import java.util.NoSuchElementException;
5	
6	/**A simple List interface that describes operations
7	 * on a list; overly simplistic, but this definition is sufficient
8	 * for instructional purposes.
9	 *
10	 * @author Terence Parr
11	 * <a href=http://www.MageLang.com>MageLang Institute</a>
12	 */
13	public interface List {
14	
15	
16		public void add(Object o); // can insert at head or append.
17		public void append(Object o);
18		public Object elementAt(int index) throws NoSuchElementException;
19		public Enumeration elements();
20		public boolean includes(Object o);
21		public int length();
22	}
23